Sewing machine



Oct. 31, 1939. R. s. KELSO 2,178.175-

I SEWING MACHINE Filed Feb. 15. 193'. 2 Sheets-Sheet 1 Oct. 31, 1939.

lllllll R. S. KELSO SEWING MACHINE Filed Feb. 13, 1937 Z-Sheets-Sheet 2 Patented Oct. 31, 1939 UNITED STATES PATENT OFFICE snwma momma:

Application February 13, 1937, Sel'lal No. 125,652

4 Claims. (01. 112-228) This invention relates to new and useful improvements in sewing machines generally, although more particularly to the rotary hook, bobbin case base, and bobbin case assembly there- One of the objects of this invention is to simplify the construction of the hook whereby the manufacture of the hook and the bobbin case base will be facilitated, and the parts can be easier assembled than heretofore.

Another object of the invention is to'provide a novel means for lubricating the hook and the bobbin case.

A further object of the invention is to provide a simple means for threading the bobbin case and for tensioning the bqbbin thread, and for locating the bobbin thread as it leaves the case at a point where it will be shielded not only from the rotary hook but also from the needle loop when the latter passes around the case, the tensioning means being constructed to prevent the needle thread loop from being caught in the threading slots.

With these and other objects in view which will more fully appear, the nature of the invention will be more clearly understood by the following description, the appended claims, and the several views illustrated in the accompanying drawings.

In the drawings:

Figure 1 is an elevation showing my invention embodied in a lock stitch machine,

Figure 2 is an enlarged elevation of the hook and bobbin case base,

Figure 3 is a side elevation of the rotary hook,

Figure 4 is an enlarged elevation of the bobbin case and bobbin assembly,

Figure 5 is a side elevation thereof,

Figure Gis a detail elevation of the opposite 0 side of the bobbin case tongue,

Figure 7 is a detail top plan of the bobbin case, and

Figure 8 is a perspective view of the bobbin case tongue.

45 Like reference numerals designate corresponding parts throughout the several figures of the drawings.

Referring to the accompanying drawings, my invention is shown as applied to a lock stitch 50 machine which includes the usual base 5, throat plate 6, presserfoot l, and vertically reciprocatory needle 3.

Supported on the base in the usual manner for cooperation with the needle is a 2-rotation hook 55 A having a hollow body 9 in which is mounted the stationary bobbin case base B, the body 9 having an outwardly extending peripheral flange Ill. The front edge of the base B is provided with an outwardly projecting peripheral flange II and attached to the outer face of the book 5 body flange It by screws I2 is an arcuate gib |3 which forms an outer bearing or retainer for the base B, the gib overlappingv the angular flange H of said base. The gib l3 thus cooperates with the body 9 to form an annular re- 10 cess for receiving the base flange By means of the removable gib |3, a very simple construction is provided which not only facilitates the manufacture of the parts but also permits of the parts being easily assembled. The lower 15 half of the base flange H is provided with spaced openings H which are in open communication with the outer periphery of the flange through the medium of slots l5. These openings tunetion to collect lint which is separated from the 20 fabric being stitched, and the lint which collects oil serves to lubricate the flanges l0 and H between the hook and the bobbin case base.

Rotatably mounted in the base B is a bobbin case 0 in which is rotatably mounted a bobbin 25 D containing the bobbin thread E.

The bobbin case C comprises an annulus l8 and an arm-I1 which is rigidly secured to the outer face of the base and extends diametrically across the same, one end of the arm extend- 3() ing beyond the annulus IE to form a radially projecting tongue l8 which projects into and is loosely fitted into a seat l9 integral with the base B. The arm ll including the tongue I8, is formed on its outer face with a longitudinal 35 recess 20 which of course extends radially with respect to the bobbin case, and forms resultant side flanges 2|, 22 on the arm proper and alined side flanges 23, 24 on the tongue,-the flanges 2|,

23 being spaced by a slot 25 and the flanges 22, 24 beingspaced by a slot 26. The left side of the tongue in rear of the flange 23 is provided with a radially extending side groove 21 which is in open communication with the slot 25.

Seated within the recess 20 is a bowed ten sion spring 28 of flat metal, the outer end of the spring projecting outwardly beyond the slots 25, 26 and into the tongue l8. The outer end of the recess 20 is concaved as at 29 and the outer end of the spring is convexed correspondingly as at 30 and is spaced slightly from said end 29 of the recess. The spring 28 is secured to the arm proper by a screw 3|, and the outer end portion of the spring is provided with longitudinally extending side flanges 32, 33 which are staggered with respect to the slots 25, 26 and therefore these flanges overlap said slots. The flanges 32, 33 are Spaced slightly from the flanges 23, 24 of the tongue.

In threading the bobbin case, the operator leads thethread E from the bobbin D through a slot 34 in the annulus to an opening 35 which is formed in the annulus directly in rear of the tongue ll, then forwardly into a slot 36 formed in the rear wall of the tongue and also along the side slot 26, then outwardly between the flange 24 of the tongue and the flange 33 of the spring, then around the outer end 30 of the spring, then inwardly between the flange 23 of the tongue and the flange 32 of the spring, then rearwardly along the slot 25, and finally outwardly along the groove 21.

From the foregoing, it will be seen that the bobbin thread D is led upwardly along the groove 21 of the tongue 18 to the last formed stitch, and consequently the thread is shielded from the hook and also from the needle loop when the latter is passing around the bobbin case base B; that inasmuch as the tongue I8 is loosely received within the base recess l9 said tongue is capable of having a slight angular movement and consequently the groove 21 functions to prevent the thread from becoming nipped between the tongue and the projection that the tongue II of the base can be easily threaded by the operator that the thread will not unthread itself from the tongue, and that the side flanges 32, 33 of the tension spring not only assist the operator in threading the tongue but also func tion to prevent the needle loop when passing around the bobbin case base from catching in the slots 25, 26 of the tongue.

It is of course to be understood that the details of structure and arrangement of parts may be variously changed and modified without departing from the spirit and scope of my invention.

I claim:

1. The combination with a rotary hook having a body disposed to rotate about a horizontal axis and provided along its front edge with an annular recess, and a bobbin case base nonrotatably mounted in said body and having a flange seated in said recess, said flange having one or more lint collecting oil holding slots extending inwardly from the lower edge portion thereof.

2. The combination with a rotary hook having a body, of a bobbin case base non-rotatably mounted therein, a tongue projecting radially beyond the periphery of the base and provided with a radial recess in its front face forming resultant side flanges, said flanges being provided with transverse thread guiding slots, and a tension spring located in said recess and having forwardly projecting side flanges overlapping said slots.

3. The combination with a rotary hook having a body, of a bobbin case base non-rotatably mounted therein, a tongue projecting radially beyond the periphery of the base and provided with a radial recess in its front face forming resultant side flanges, said flanges being provided with transverse thread guiding slots, and a tension spring located in said recess, the side of the tongue farthest in advance of the hook beak during its rotation being provided with an upwardly extending thread groove in open communication with the adjacent transverse slot.

4. The combination with a rotary hook having a body, of a bobbin case base non-rotatably mounted therein, a tongue projecting radially beyond the periphery of the base and provided with a radial recess in its front face forming resultant side flanges, said flanges being provided with transverse thread guiding slots, and a tension spring located in said recess and having forwardly projecting side flanges overlapping said slots, the side of the tongue farthest in advance of the hook beak during its rotation being provided with an upwardly extendingthread groove in open communication with the adjacent transverse slot, the opposite side of the tongue being provided with a lateral thread groove in open communication with the adjacent transverse slot.

RALPH SIMPSON KELSO. 

